Non-Patent Document 1 and Non-Patent Document 2 define the specifications for the RLC protocol and the MAC protocol. According to those protocols, a data processing unit, called a PDU (Protocol Data Unit), is defined for each layer (see “6 Protocol data units, formats, and parameters” in Non-Patent Documents 1 and 2). A PDU used in the RLC layer is called an RLC PDU, and a PDU used in the MAC layer is called a MAC PDU. There are two types of RLC PDU: an RLC data PDU in which data is stored and an RLC control PDU that is used for control.
Patent Document 1 discloses a data processing method for use on a receiver's device in a wireless communication system. This data processing method, provided for use on an HSDPA (High Speed Downlink Packet Access) receiver's device whose MAC layer has the retransmission-function, comprises a step for transferring a data unit and the CRC (Cyclic Redundancy Code) check result, related to the data unit, from the MAC layer to the RLC layer; a step in the RLC layer for determining if the CRC check result, transferred from the MAC layer, indicates whether or not the data unit has an error; and a step for discarding the data unit if the data unit has an error and an error handling method is not provided.